1. Field of the Invention
This invention relates to a rotary electric machine capable of changing its output characteristic and to a vehicle driven by the rotary electric machine.
2. Background Art
A conventional technique related to the electric motor includes a gap between the stator teeth and the rotor magnet being adjusted.
As shown in FIG. 6, when a fastening-adjusting member 160 is loosened by an operation made to a head 162, a bushing 146 and a drum rotary member 125 move away from each other with the restoring force of a resilient member 161. As a result, the gap G between a rotor magnet 141 and a motor stator 130 increases. When the fastening-adjusting member 160 is tightened, the bushing 146 and the drum rotary member 125 approach each other, so that the gap G decreases.
The above constitution is devised to cope with the change in the specification of a product. In other words, the device for adjusting the gap between rotor and stator related to an axial gap motor is disclosed as an embodiment capable of adjusting the gap only before the device being attached to the product, not as an embodiment capable of adjusting the gap while the product is in operation for operating the product under an optimum condition. While part of the specification describes electromagnetic operation and manual operation, no specific embodiment is disclosed. This is due to the absence of the necessity for examining a means of solving the problem of actively changing the characteristic of an electric motor such as the driving source of an electric motor vehicle by optionally changing the gap while the product is in operation.
Another conventional electric motor relates to a reel motor for rotary-driving a reel of a tape recorder. The invention relates to an axial gap motor, disclosing a manner of adjusting the gap between rotor and stator by controlling the axial displacement using both a spring attached to a shaft and magnetic force of an electromagnet by changing the current flowing through the electromagnet in proportion to the current flowing through the motor. However, the gap adjustment in consideration of the motor rotational speed cannot be made with the combination of the spring and the electromagnet proportional to the current flowing through the motor. When the gap, as in the electric motor vehicle, must be adjusted to cope with the constant changes in the road conditions, such as uphill gradient and vehicle speed, it is impossible to do so with a gap controlling device that makes all such conditions represented with the current flowing through the motor. Therefore, a more active and intelligent gap adjusting device is needed.
Another conventional electric motor relates to a control device for a generator for use in vehicles. According to the invention, the generator characteristic is changed by adjusting the gap of a radial gap motor. However, because the rotor is displaced with a solenoid, fine control cannot be made and it is hard to apply the device to the motor in electric motor vehicles that require fine control according to the driving force and the vehicle speed. It is especially hard to realize the control in an axial gap type that exhibits a wide change in the characteristic with a slight change in the gap. While an example is shown there in which the stator is moved with a motor and screw, it is impossible to move the rotor, while it is rotating, with such a constitution.